Zhu Dan, Jiang Ming-Yi, Tan Ming-Pu
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Zhi Wu Sheng Li Yu Fen Zi Sheng Wu Xue Xue Bao. 2006 Oct;32(5):519-26.
In maize (Zea mays L.) cells, the sources of apoplast hydrogen peroxide (H(2)O(2)) induced by abscisic acid (ABA) has been proposed. Histochemical and cytochemical localization of ABA-induced H(2)O(2) production in leaves of maize was examined, using 3, 3-diaminobenzidine (DAB) and cerium chloride (CeCl(3)) staining respectively. Pretreatment with two different inhibitors for each enzymes, with diphenylene iodonium (DPI) and imidazole against NADPH oxidase, NaCN and NaN(3) against peroxidases (POD), and quinacrine and guazatine against polyamine oxidases (PAO), reduced H(2)O(2) accumulation induced by ABA. Among them, NADPH oxidase inhibitors arrested the production of apoplastic H(2)O(2) most strongly (Figs.1,2). Further studies showed that exogenous ABA treatment could enhance the activities of plasma membrane (PM) NADPH oxidase, cell wall POD and apoplast PAO significantly. Moreover, the activity of PM NADPH oxidase kept increasing before 1.5 h, while the other two enzymes began to decrease at 0.5 h within 2 h by ABA treatment (Fig.3). The results suggest that exogenous ABA treatment can lead to significant increases in H(2)O(2) accumulation in apoplast through up-regulating the activities of the PM NADPH oxidases, cell wall POD and apoplast PAO, of which the first one plays a central role in ABA-induced apoplastic H(2)O(2) accumulation.
在玉米（Zea mays L.）细胞中，脱落酸（ABA）诱导质外体过氧化氢（H₂O₂）的来源已被提出。分别使用3,3 - 二氨基联苯胺（DAB）和氯化铈（CeCl₃）染色，检测了ABA诱导玉米叶片中H₂O₂产生的组织化学和细胞化学定位。用针对每种酶的两种不同抑制剂进行预处理，用二苯基碘鎓（DPI）和咪唑抑制NADPH氧化酶，用NaCN和NaN₃抑制过氧化物酶（POD），用喹吖因和胍嗪抑制多胺氧化酶（PAO），可减少ABA诱导的H₂O₂积累。其中，NADPH氧化酶抑制剂对质外体H₂O₂产生的抑制作用最强（图1、2）。进一步研究表明，外源ABA处理可显著增强质膜（PM）NADPH氧化酶、细胞壁POD和质外体PAO的活性。此外，在1.5小时之前，质膜NADPH氧化酶的活性持续增加，而在ABA处理2小时内，另外两种酶在0.5小时开始下降（图3）。结果表明，外源ABA处理可通过上调质膜NADPH氧化酶、细胞壁POD和质外体PAO的活性，导致质外体中H₂O₂积累显著增加，其中质膜NADPH氧化酶在ABA诱导的质外体H₂O₂积累中起核心作用。
